Draw a mountain given altitude

Question

Take an array of nonnegative integers, such as [1, 0, 0, 1, 2, 4, 2, 0]. Then, draw that as a mountain where the integers represent altitude:

You may use any printable non-whitespace character in place of x, and adding padding or whitespace after lines or the output is fine (but not required). You may optionally take one indexed inputs. Transposing the output is not allowed, but returning an array of lines is fine.

This is code-golf, so shortest answer (in bytes) per language wins.

May I print the answer with extra columns of spaces between each column? — FZs, Jun 26 at 9:40
@JonathanAllan I don't think I mentioned anything either way on that in chat, but I think it'd fall under standard I/O in one way or another. It's very much an edge case though, so I think putting it in the challenge body is unnecessary. I did edit earlier to include the list of lines thing, though. Thanks! — Redwolf Programs, Jun 27 at 21:50

lyxal · Accepted Answer · 2021-06-26 07:59:51Z

17

+100

Vyxal, 4 bytes

×꘍R§

Try it Online!

That's right, it's flagless.

Explained

×꘍    # [(n * " ") + "*" for n in input]
  R   # [x[::-1] for x in ^]
   §  # vertically join (rotate) ^

Using the L flag would make it 3 bytes.

answered Jun 26 at 7:59

lyxal

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dingledooper · Accepted Answer · 2021-06-26 07:28:53Z

11

Python 2, 66 bytes

a=input()
n=max(a)
while~n:print''.join(' x'[x==n]for x in a);n-=1

Try it online!

answered Jun 26 at 7:28

dingledooper

14.6k1 gold badge17 silver badges81 bronze badges

\$\begingroup\$ I'm new to golfing, could you please explain what the ~ in the while~n: stands for ? \$\endgroup\$
– Ubikuity
Jun 27 at 17:12
\$\begingroup\$ @Ubikuity It is the bitwise NOT operator. See docs.python.org/3/reference/expressions.html#index-96 \$\endgroup\$
– Unmitigated
Jun 27 at 17:42
1

\$\begingroup\$ See golfing tips for Python. ~ is the logical operator not. So while~n:<<…>>;n-=1 is a sort of for loop for n decreasing until it’s 0 (not n is True if n not equal to 0; for n=0, it’s False). \$\endgroup\$
– agtoever
Jun 27 at 17:45
1

\$\begingroup\$ @agtoever n actually decreases until it reaches -1. ideone.com/GEM9L1 \$\endgroup\$
– Unmitigated
Jun 29 at 13:53
\$\begingroup\$ @Unmitigated you’re completely right. \$\endgroup\$
– agtoever
Jun 29 at 13:55

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ovs · Accepted Answer · 2021-06-26 09:03:11Z

9

05AB1E (legacy), 5 bytes

$úζR»

Try it online!

$        # push "1" and the input
 ú       # for each integer in the input,
         # pad "1" with this many spaces in the front
  ζ      # tranpose, padding with spaces
   R     # reverse, the mountains should not be upside down
    »    # join by newlines

answered Jun 26 at 9:03

ovs

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1

\$\begingroup\$ » can be removed. \$\endgroup\$
– Makonede
Jun 30 at 2:49

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pxeger · Accepted Answer · 2021-06-26 17:05:53Z

7

Zsh, ⁶⁶ 63 bytes

s=${(l/${${(On)@}[1]}*#/)}
for x;s[++i+$#s-#*x]=.
fold -$#<<<$s

Attempt This Online!

-3 thanks to JoKing, but still probably too long.

Explanation:

${${(On)@}[1]}: get the maximum input
s=${(l/*#/)}: construct a string of spaces which is (number of inputs) × (maximum of inputs) in length
for x;s[++i+$#s-#*x]=.: set the correct index of the string to a . for each element
fold -$#<<<$s: line-wrap the string at (number of inputs) in length

edited Jun 26 at 17:05

answered Jun 26 at 8:53

pxeger

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1

\$\begingroup\$ Only familiar with bash, but would something like sort -n|tail -1 save bytes for getting the max? \$\endgroup\$
– Jonah
Jun 26 at 15:05
\$\begingroup\$ @Jonah That method doesn't turn out to be shorter, but Zsh has its own builtin way to sort things which I should have considered, so thanks for the hint anyway! \$\endgroup\$
– pxeger
Jun 26 at 17:03

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AviFS · Accepted Answer · 2021-06-26 07:41:32Z

6

APL(Dyalog Unicode), 18 bytes ^SBCS

{⊖⍉⍕⍪'x',¨⍨⍵⍴¨' '}

{          ⍝ Open function
⊖⍉         ⍝ Flip diagonally and then vertically
⍕          ⍝ Make table into multiline string
⍪           ⍝ Display one element per row
'x',¨⍨      ⍝ Append an 'x' to each element
⍵⍴¨' '      ⍝ Duplicate each space 'input' times
}           ⍝ Close function

Try it on online!

edited Jun 26 at 7:41

answered Jun 26 at 7:29

AviFS

1,86510 silver badges24 bronze badges

2

\$\begingroup\$ ⊖⍉↑'x'↑¨⍨-1+⎕ 13 \$\endgroup\$
– rak1507
Jun 26 at 9:17
\$\begingroup\$ @rak1507 Thanks for the idea! Not sure I understand, though. It doesn't seem to work. Will play around with it more later! \$\endgroup\$
– AviFS
Jun 26 at 10:17
\$\begingroup\$ the 13 is the byte count \$\endgroup\$
– rak1507
Jun 26 at 11:00
\$\begingroup\$ rak's comment is a full program, here is a TIO link for it. I'm not sure how to use it on APLgolf \$\endgroup\$
– ovs
Jun 26 at 11:44
1

\$\begingroup\$ Sounds good, thanks a bunch @rak1507. I'm sure ovs is, yours was just a significant change so I wanted you to get the rep & credit if you wanted! \$\endgroup\$
– AviFS
Jun 27 at 20:02

| Show 3 more comments

Razetime · Accepted Answer · 2021-06-26 13:37:28Z

6

Red, 91 bytes

func[a][i: last sort copy a until[forall a[prin either a/1 = i[1][sp]]print""0 > i: i - 1]]

Try it online!

-6 bytes from Galen Ivanov.

edited Jun 26 at 13:37

answered Jun 26 at 7:51

Razetime

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\$\begingroup\$ 91 bytes with some minor modifications. \$\endgroup\$
– Galen Ivanov
Jun 26 at 13:33

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caird coinheringaahing · Accepted Answer · 2021-06-26 15:31:56Z

6

Jelly, 7 bytes

Ṭ€z0Ṛo⁶

Try it online!

Outputs a list of lines. +1 byte (append Y) if unacceptable.

Takes input 1 indexed, uses 1 as the mountain character

How it works

Ṭ€z0Ṛo⁶ - Main link. Takes a list L on the left
 €      - Over each element in L:
Ṭ       -   Untruthy; Map each n to [0, 0, ..., 1] with n-1 zeros
  z0    - Transpose, padding with zeros
    Ṛ   - Reverse
     o⁶ - Replace 0s with spaces

edited Jun 26 at 15:31

answered Jun 26 at 10:01

caird coinheringaahing

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\$\begingroup\$ Strictly speaking, even if a list of lines is acceptable you would still need to be allowed to use an integer in place of a character to remove the Y ("You may use any printable non-whitespace character in place of x"). \$\endgroup\$
– Jonathan Allan
Jun 26 at 15:51
\$\begingroup\$ @JonathanAllan It appears as though Y doesn't actually coerce integers into strings: Try it online!. However, OP confirmed in chat that both a list of lines and mixing characters/digits was fine \$\endgroup\$
– caird coinheringaahing
Jun 27 at 9:02
\$\begingroup\$ No it does not, but with it the code would work as a full program due to Jelly's implicit, smashing print. \$\endgroup\$
– Jonathan Allan
Jun 27 at 10:05
\$\begingroup\$ The post has not been updated yet to say non-charactrers are acceptable. It's best to stick to the current wording and give the potential save than the other way around. \$\endgroup\$
– Jonathan Allan
Jun 27 at 10:09

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Jonah · Accepted Answer · 2021-06-26 23:19:09Z

6

J, 17 bytes

[:|.@|:' x'#~,.&1

Try it online!

^{+6 thanks to Lynn for spotting a bug in the original solution: ' x'{~=\:~. This approach can be made to work but it's no longer golfy: ' x'{~]=/~[:i.1-@+>./}

how

,.&1 Zip input with 1:
```
1 1
0 1
0 1
1 1
2 1
4 1
2 1
0 1
```

' x'#~ Duplicate ' x' according to these pairs

[:|.@|: Rotate left:
```
     x  

    x x 
x  x    
 xx    x
```

edited Jun 26 at 23:19

answered Jun 26 at 14:35

Jonah

23k4 gold badges24 silver badges66 bronze badges

\$\begingroup\$ Good spot, thanks. Fixed solution not as nice though :( \$\endgroup\$
– Jonah
Jun 26 at 22:54
\$\begingroup\$ @Lynn Original approach can be salvaged ' x'{~]=/~[:i.1-@+>./ but it's no longer shorter. \$\endgroup\$
– Jonah
Jun 26 at 23:15

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Jonathan Allan · Accepted Answer · 2021-06-27 21:55:50Z

Jelly, 6 bytes

=ⱮṀṚo⁶

A monadic Link that accepts a list of positive integers (the 1-indexed option) and yields a list of lists of characters and integers (1 being the choice for x).

Try it online! (The footer joins with newlines and then Jelly's implicit, smashing print produces the output.)

How?

=ⱮṀṚo⁶ - Link: list of integer heights, H
  Ṁ    - maximum (H) -> M
 Ɱ     - map across (h in [1..M]) with:
=      -   (H) equals (h) (vectorises)
   Ṛ   - reverse -> X
     ⁶ - space character
    o  - (X) logical OR (' ') (vectorises)

Neil · Accepted Answer · 2021-06-26 07:53:17Z

4

Charcoal, 6 bytes

↑ＥＡ◧xι

Try it online! Link is to verbose version of code. 1-indexed. Explanation:

  Ａ     Input array
 Ｅ      Map over elements
    x   Literal string `x`
   ◧    Left-padded to width
     ι  Current element
↑       Print rotated

answered Jun 26 at 7:53

Neil

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Shaggy · Accepted Answer · 2021-06-26 11:09:49Z

4

Japt `-R`, 7 bytes

1-indexed, using " for the peaks.

£QùXÃÕÔ

Try it

£QùXÃÕÔ     :Implicit input of array
£           :Map each X
 Q          :  Quotation mark
  ùX        :  Left pad with spaces to length X
    Ã       :End map
     Õ      :Transpose
      Ô     :Reverse
            :Implicit output joined with newlines

edited Jun 26 at 11:09

answered Jun 26 at 9:03

Shaggy

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G B · Accepted Answer · 2021-06-26 16:40:52Z

4

Ruby, 51 bytes

->a{(-a.max..0).map{|y|a.map{|x|x==-y ??x:' '}*''}}

Try it online!

answered Jun 26 at 16:40

G B

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Underslash · Accepted Answer · 2021-06-26 19:13:01Z

3

Vyxal, 11 9 bytes

-2 bytes through auto-vectorizing

ð*×+ðÞṪṘ⁋

ð*            # vectorised n spaces
  ×+          # append "*"
     ðÞṪ      # transpose with space as filler
        Ṙ⁋    # reverse and join by newline

Try it Online!

edited Jun 26 at 19:13

answered Jun 26 at 7:28

Underslash

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FZs · Accepted Answer · 2021-06-27 05:58:01Z

3

JavaScript (Node.js), _⁷⁷ _⁷⁴ _⁷³ 70 bytes

-1 thanks to @RecursiveCo.
-3 thanks to @m90's idea

a=>{for(i=Math.max(...a);i;i--)console.log(a.map(e=>i^e&&' ').join``)}

Try it online!

Takes one-indexed input.

edited Jun 27 at 5:58

answered Jun 26 at 9:25

FZs

2558 bronze badges

1

\$\begingroup\$ -1 bytes for your first program: see this link \$\endgroup\$
– user100690
Jun 26 at 11:46
\$\begingroup\$ @RecursiveCo. Good idea, applies to both of my programs. Edited in. (+ thanks for tidying up my header & footer) \$\endgroup\$
– FZs
Jun 26 at 12:53
1

\$\begingroup\$ A further improvement is to replace 'x' with 1 (which gets automatically stringified by join), since any printable non-whitespace character is accepted. \$\endgroup\$
– m90
Jun 26 at 22:55
\$\begingroup\$ @m90 Good point! Thinking further, I can even get rid of the literal 1 by using the 0 returned by the XOR. Thanks for the idea, merged. \$\endgroup\$
– FZs
Jun 27 at 5:59
\$\begingroup\$ Switch to the V8 engine on TIO and you can use print. \$\endgroup\$
– Shaggy
Jun 27 at 20:05

| Show 1 more comment

Dominic van Essen · Accepted Answer · 2021-06-27 23:06:15Z

3

R, 65 bytes

function(a)for(i in max(a):0)cat(c(' ','x')[1+(a==i)],'
',sep='')

Try it online!

answered Jun 27 at 23:06

Dominic van Essen

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Grysik · Accepted Answer · 2021-06-30 07:21:01Z

3

Python 3, 67 bytes

lambda x:[[v==i and'*'or' 'for v in x]for i in range(max(x),-1,-1)]

Try it online!

for i in range(max(x),-1,-1) -> identify how high the mountain will be, max value is first line (top), so start from max, iterate to 0

[v==i and'*' or' ' for v in x] -> for every integer in input set it as * if height matches current line, set it whitespace otherwise.

[EDIT] as per @hyper-neutrino suggestion to get 3 bytes less, and wrapped in lambda as per @Razetime comment

edited Jun 30 at 7:21

answered Jun 29 at 13:31

Grysik

1312 bronze badges

\$\begingroup\$ Welcome to Code Golf! You can remove three spaces here: after '*', after ' ', and after the first ]. You may also be interested in our Tips for golfing in Python. \$\endgroup\$
– hyper-neutrino ♦
Jun 29 at 13:37
\$\begingroup\$ hardcoding is not allowed as per standard i/o, so you need to wrap your code in a function. \$\endgroup\$
– Razetime
Jun 29 at 14:17
\$\begingroup\$ @Razetime could be like it's now, wrapped in lambda, so input is lambda arg? \$\endgroup\$
– Grysik
Jun 30 at 7:22
\$\begingroup\$ Yep, correct. You may want to read this meta post if you have any doubts. \$\endgroup\$
– Razetime
Jun 30 at 8:04
\$\begingroup\$ lambda a:[[' x'[i==j]for j in a]for i in range(max(a),-1,-1)] \$\endgroup\$
– Jitse
Jun 30 at 8:22

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att · Accepted Answer · 2021-06-26 18:14:04Z

2

Wolfram Language (Mathematica), 44 bytes

Print@@@Table[" "Unitize[#+i],{i,-Max@#,0}]&

Try it online!

Prints the mountain, using 0 instead of x.

Remove the Print@@@ for -8 bytes if an array of characters and numbers is acceptable output.

answered Jun 26 at 18:14

att

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Luis Mendo · Accepted Answer · 2021-06-26 21:08:34Z

2

Octave / MATLAB, 43 bytes

@(x)flip([accumarray([x find(x)],3)+32 ''])

Anonymous function that inputs a 1-based column vector and outputs a char matrix with # and

Try it online!

edited Jun 26 at 21:08

answered Jun 26 at 18:30

Luis Mendo

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DLosc · Accepted Answer · 2021-06-27 06:13:42Z

Pip `-l`, 10 bytes

R:sXg.0ZDs

Takes the integers as command-line arguments. Outputs using 0 in place of x. Try it here! Or, here's an 11-byte equivalent in Pip Classic: Try it online!

Explanation

            g is list of cmdline args; s is space (implicit)
  sXg       Convert each arg to a string of that many spaces
     .0     Append 0 to each string of spaces
       ZDs  Transpose, extending shorter strings with a default value of space
R:          Reverse the resulting list
            Autoprint, one row per line (-l flag)

hakr14 · Accepted Answer · 2021-06-27 23:03:34Z

2

Canvas, 7 bytes

｛ ×x＋］↶

Try it here!

answered Jun 27 at 23:03

hakr14

3,3361 gold badge7 silver badges14 bronze badges

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hakr14 · Accepted Answer · 2021-06-27 23:05:17Z

2

Pyth, 7 bytes

_.tm+*;

Try it here!

answered Jun 27 at 23:05

hakr14

3,3361 gold badge7 silver badges14 bronze badges

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Draw a mountain given altitude

21 Answers 21

Vyxal, 4 bytes

Explained

Python 2, 66 bytes

05AB1E (legacy), 5 bytes

Zsh, ⁶⁶ 63 bytes

APL(Dyalog Unicode), 18 bytes ^SBCS

Red, 91 bytes

Jelly, 7 bytes

How it works

J, 17 bytes

how

Jelly, 6 bytes

How?

Charcoal, 6 bytes

Japt `-R`, 7 bytes

Ruby, 51 bytes

Vyxal, 11 9 bytes

JavaScript (Node.js), _⁷⁷ _⁷⁴ _⁷³ 70 bytes

R, 65 bytes

Python 3, 67 bytes

Wolfram Language (Mathematica), 44 bytes

Octave / MATLAB, 43 bytes

Pip `-l`, 10 bytes

Explanation

Canvas, 7 bytes

Pyth, 7 bytes

Your Answer

Not the answer you're looking for? Browse other questions tagged code-golf string or ask your own question.

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Draw a mountain given altitude

21 Answers 21

Vyxal, 4 bytes

Explained

Python 2, 66 bytes

05AB1E (legacy), 5 bytes

Zsh, 66 63 bytes

APL(Dyalog Unicode), 18 bytes SBCS

Red, 91 bytes

Jelly, 7 bytes

How it works

J, 17 bytes

how

Jelly, 6 bytes

How?

Charcoal, 6 bytes

Japt -R, 7 bytes

Ruby, 51 bytes

Vyxal, 11 9 bytes

JavaScript (Node.js), 77 74 73 70 bytes

R, 65 bytes

Python 3, 67 bytes

Wolfram Language (Mathematica), 44 bytes

Octave / MATLAB, 43 bytes

Pip -l, 10 bytes

Explanation

Canvas, 7 bytes

Pyth, 7 bytes

Your Answer

Sign up or log in

Post as a guest

Not the answer you're looking for? Browse other questions tagged code-golf string or ask your own question.

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Related

Hot Network Questions

Zsh, ⁶⁶ 63 bytes

APL(Dyalog Unicode), 18 bytes ^SBCS

Japt `-R`, 7 bytes

JavaScript (Node.js), _⁷⁷ _⁷⁴ _⁷³ 70 bytes

Pip `-l`, 10 bytes